High Temperature Fabry-Perot Based Strain Sensor for Ceramic Cross Flow Filters

Abstract

The objectives of this research program were to develop instrumentation methods to allow in-situ analysis of ceramic cross flow (CXF) filters.Information from such instrumentation is needed to determine how the filters perform during operation, how subsequent filter and combustor designs may be improved based on the knowledge of such performance, and how and where damage and degradation occur. CXF filters are used for hot gas clean-up of coal-fired power generation systems, such as pressurized fluidized-bed combustors and integrated gasifier-combined cycles.The ceramic cross flow filter is analogous to cross-flow he at exchangers, except gas is passed between channels instead of thermal energy (heat) . The CXF filters are made from multiple layers of thin , flat, porous ceramic (alumina or silicon nitride) with grooves which form channels in each layer.The layers are stacked to form a filter element that is approximately 30 cm high by 30 cm long by 10 cm wide. Consecutive layers of ceramic are oriented such that the channels formed are perpendicular to each other. One of the sides of the filter element is sealed. Gas enters the filter through the openings of the channel on the two sides that are perpendicular to the sealed end, permeates the porous ceramic, and exits through the openings on the side that is parallel to the sealed end.Particles are removed from the gas stream by direct interception, diffusion, and inertial impaction.The filter elements are periodically backflushed with abrief, high-pressure cleaning pulse of air or nitrogen to remove the particles that were deposited on the dirty side of the dividing walls. The CXF filter operates in an extremely corrosive and erosive environment while undergoing temperatures between 500 and 900 0 C and pressures up to 2500 kPa.